1. IN THE VAPOR PHASE PROCESS OF AMMOXIDATION TO FORM NITRILES BY REACTION OF AMMONIA AND AN ORGANIC REACTANT SELECTED FROM THE ROUP OF ALKYL-SUBSTITUTED AROMATIC, ALIPHATIC, AND ALICYCLIC HYDROCARBON COMPOUNDS AND ALKYLSUBSTITUTED HETEROCYCLIC COMPOUNDS AND IN THE ABSENCE OF ADDED OXYGEN, THE IMPROVEMENT OF REDUCING THE FORMATION OF CARBON OXIDES DURING REACTION WHICH COMPRISES USING AS CATALYST A COMPOSITION WHICH IS ESSENTIALLY FREE OF V2O5 AND COMPRISED OF A VANADIUM OXIDE WHICH IS INTERMEDIATE V2O5 AND V2O3, SAID CATALYST BEING REMOVED FROM SAID PROCESS AND REGENERATED TO THE INTERMEDIATE OXIDE PRIOR TO ITS IN-SITU CONVERSION TO SIGNIFICANT AMOUNTS OF V2O3.